Resource utilization for uplink transmission based on indicated interference

ABSTRACT

According to a disclosed example, an intention of a first wireless communication device to use a first power level and a first time-frequency resource for up-link transmission to a first cellular communication network is detected. At a second wireless communication device, a signal is received from the first device indicative of up-link transmission. The second device determines whether or not an interference (caused by the up-link transmission of the first device and affecting a down-link reception of the second device from a second cellular communication network at a second power level in a second time-frequency resource) has a third power level associated with the first power level that exceeds a power level threshold associated with the second power level. The second device transmits an interference indication to the first device using a third time-frequency resource if it is determined that the third power level exceeds the power level threshold, and the interference indication is received at the first device. The first device determines whether or not to use the first time-frequency resource for up-link transmission based on the interference indication. Corresponding computer program product, arrangements and wireless communication device are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. application Ser. No.15/030,048 filed Apr. 15, 2016 (371(c) date), which is a 35 U.S.C. § 371national stage of international application PCT/EP2013/071620 filed Oct.16, 2013. All of these earlier applications are hereby incorporatedherein by reference in their entireties.

TECHNICAL FIELD

The present invention relates generally to the field of utilization oftime/frequency resources in cellular communication systems. Moreparticularly, it relates to utilization of resources for uplinktransmission.

BACKGROUND

To distribute communication resources between downlink (DL) and uplink(UL) transmission, some wireless communication systems employ apartition of the time dimension resources and assign different timedimension resource elements to uplink and downlink transmissionrespectively. One example of such an approach is the Time DivisionDuplex (TDD) operation of the Third Generation Partnership Project(3GPP) standard Universal Mobile Telecommunication Standard—Long TermEvolution (UMTS LTE).

In TDD, transmission in the uplink and in the downlink is typicallyperformed using the same carrier frequency (i.e. uplink and downlinkshare the same carrier frequency). This is in contrast to FrequencyDivision Duplex (FDD) operation where different carriers are used foruplink and downlink transmission respectively. Thus, one advantage ofTDD compared to FDD is that only one carrier is needed forcommunication.

Furthermore, TDD is (at least in theory) a flexible approach sinceallocation of the available time dimension resources (e.g. in terms ofsubframes of an UMTS LTE system) to uplink and downlink, respectively,may be adapted to a current situation. For example, the allocation oftime dimension resources may be adapted based on a current traffic needsuch that—compared to a default allocation—more time dimension resourcesare allocated to uplink transmission if there is a need to transmit ahigher than normal amount of data in the uplink and vice versa. In UMTSLTE, one example approach to flexibly allocate time dimension resourcesmay be referred to as a dynamically reconfigurable UL/DL allocationbased on instantaneous traffic.

Flexible allocation of time dimension resources may, however, result insome difficulties in a practical system implementation. FIG. 1 is aschematic drawing illustrating one such potential problem.

In FIG. 1, a first wireless communication device 101 communicates with anetwork node 111 of a first cellular communication network and a secondwireless communication device 102 communicates with a network node 112of a second cellular communication network. The first and secondcellular communication networks may be the same cellular communicationnetwork or different cellular communication networks. If allocation oftime dimension resources results in an uplink transmission 121 by thewireless communication device 101 being executed simultaneously as adownlink transmission 122 by the network node 112, there is a risk thatinterference 141 from the first wireless communication device 101(caused by the uplink transmission 121) reaches the second wirelesscommunication device 102 and (more or less severely) interferes withreception of the downlink transmission 122 at the second wirelesscommunication device 102. The area 131 marks a “dead zone” or “coveragehole” where downlink reception is severely impaired by an uplinkreception from the first wireless communication device 101.

For example, in practical TDD deployments according to UMTS LTE, thepossibility to use different UL/DL subframe allocation patterns indifferent cells is rather limited. This is the case both for differentcells using the same carrier frequency and for different cells usingadjacent carrier frequencies. The limitation is (at least partly) due tothe large dynamics in a communication system, where the power level of areceived signal may be as low as approximately −100 dBm white the powerlevel of a transmitted signal may be above e.g. 20 dBm (i.e. a powerdifference or dynamic range of 120 dB). Therefore, if one devicetransmits with a high power level at the same time as another devicereceives a signal with a low power level, the power level of theinterference experienced at the receiving device may be (up to) 120 dBlager than the power level of the desired signal considering that thedevices may be located close to each other.

Assuming ideal transceivers it would be possible to deploy differentUL/DL allocation patterns for different cells using adjacent TDDcarriers. However, due to real-world transceiver imperfections (e.g.non-linear elements) there will be leakage of the uplink signaltransmitted on one of the carriers into the spectrum of the signal to bereceived in the other carrier (which could be adjacent). Thus,interference may typically be experienced also in adjacent channels. TheUMTS LTE specification includes requirements that adjacent channelleakage should be in the range of 30-40 dB for a User Equipment (LIE).Hence, the adjacent channel interference may be (up to) 120−30=90 dB(the in-band power difference of 120 dB is reduced to 80-90 dB adjacentchannel power difference if the devices are located close to each otherand, thus, the path loss between them is low).

One way of attempting to avoid the situation illustrated in FIG. 1 maybe by alignment of the time dimension resource allocation patterns ofthe base stations, which typically makes the allocation less flexible(or not flexible at all).

Another way to attempt avoidance of the situation illustrated in FIG. 1may be by having coordination between the network nodes of the first andsecond cellular communication networks, which may not be possible if thenetwork nodes do not have a suitable connection to each other (e.g. ifthey belong to different operators). Even if coordination is possible,there may be a lack at the allocating network node of information neededto perform the coordination efficiently (e.g. which devices are in thevicinity of the first wireless communication device 101). In suchsituations, the flexible allocation may be based on a worst casescenario (e.g. not allocating extra uplink slots to the first device ifone or more active devices are present in the entire area covered by anadjacent network node), which typically makes the allocation toorestrictive and less flexible.

WO 2009/063001 A2 discloses adaptation of allocation of up-link anddown-link subframes in wireless communication systems. A control unit ata base station may detect particular problem scenarios and determinethat interference between two (or more) particular mobile terminals hasoccurred or is likely. In one example, by comparing schedulinginformation, time alignment values, signal quality reports, and thelike, the base station control unit may determine that two half-duplexmobile terminals connected to the serving base station are transmittingsimilar SIR values and have similar timing alignment such that atransmission for one terminal coincides with reception at anotherterminal. In this case, a new uplink downlink subframes allocationpattern is sent to at least one of the mobile terminals. This approachis only possible for terminals connected to the same serving basestation and when the control unit has access to the schedulinginformation, etc. of both the terminals.

Thus, if flexible allocation of time dimension resources results in asituation where uplink transmission is performed by a first wirelesscommunication device in a first cellular communication network and theuplink transmission may cause interference at a second wirelesscommunication device during downlink reception by the second wirelesscommunication device in a second cellular communication network, thereis a risk of the flexible allocation of time dimension resources causingproblems to the communication in the second cellular communicationnetwork.

Such a situation may arise, for example, when the first wirelesscommunication device performs uplink transmission in a time dimensionresource that is normally allocated for downlink transmission whichresults in the allocation patterns of the base station beingnon-aligned.

An alternative or additional example of the above situation arising iswhen time dimension resource allocation patterns of the base stationscommunicating, respectively, with the first and second wirelesscommunication devices are not coordinated. This may be the case, forexample, if the first and second cellular communication networks belongto different operators. Then, the interference may occur at the adjacentchannel in the worst case.

A yet alternative or additional example of the above situation arisingis when there is no information at an allocating network node (e.g. thenetwork node 111 of FIG. 1) regarding distances between a device to beallocated extra uplink resources (e.g. the first wireless communicationdevice 101 of FIG. 1) and other devices that may be interfered bytransmission using the extra uplink resources. This may be the case, forexample, if the necessary system information cannot be exchanged betweenthe network nodes of the first and second cellular communicationnetworks. Therefore, even if there is some allocation patterncoordination between network nodes, such coordination may be ineffectivedue to lack of the distance information above.

Therefore, there is a need for methods and devices that enable flexibletime dimension resource allocation while managing potential interferencecaused by the flexibility.

SUMMARY

It should be emphasized that the term “comprises/comprising” when usedin this specification is taken to specify the presence of statedfeatures, integers, steps, or components, but does not preclude thepresence or addition of one or more other features, integers, steps,components, or groups thereof.

It is an object of some embodiments to obviate at least some of theabove disadvantages and to provide methods and devices that enableflexible time dimension resource allocation while managing potentialinterference caused by the flexibility.

According to a first aspect, this is achieved by a method for a firstwireless communication device adapted to communicate with a firstcellular communication network.

The method comprises detecting an intention of the first wirelesscommunication device to use a first power level and a firsttime-frequency resource for up-link transmission to the first cellularcommunication network.

The method also comprises receiving an interference indication from asecond wireless communication device in a third time-frequency resource.The interference indication is indicative of whether or not aninterference (caused by the up-link transmission of the first wirelesscommunication device using the first power level and the firsttime-frequency resource and affecting a down-link reception of thesecond wireless communication device from a second cellularcommunication network at a second power level in a second time-frequencyresource) has a third power level associated with the first power levelthat exceeds a power level threshold associated with the second powerlevel.

The method further comprises determining whether or not to use the firsttime-frequency resource for up-link transmission based on theinterference indication.

Determining whether or not to use the first time-frequency resource forup-link transmission may, for example, comprise determining to use thefirst time-frequency resource for up-link transmission or determining tonot use the first time-frequency resource for up-link transmission.Determining to not use the first time-frequency resource for up-linktransmission may comprise one or more of determining to seize using thefirst time-frequency resource for up-link transmission, determining toavoid using the first time-frequency resource for up-link transmission,and determining to prevent (or prohibit) use of the first time-frequencyresource for up-link transmission.

The interference may be an expected interference or an actualinterference. The up-link transmission causing the interference may becommenced (or started) before or after receiving the interferenceindication. If the up-link transmission causing the interference iscommenced after receiving the interference indication, the interferencemay be an expected interference caused by the up-link transmission,which may be an intended up-link transmission. If the up-linktransmission causing the interference is commenced before receiving theinterference indication, the interference may be an expected or anactual interference.

That the third power level (of the interference) is associated with thefirst power level (of the up-link transmission) may comprise that thethird power level is equal to a scaling factor (i.e. a third power levelscaling factor) multiplied with the first power level. The third powerlevel scaling factor may be based on (e.g. equal to) a path loss betweenthe first and second wireless communication devices. Alternatively oradditionally, the third power level scaling factor may be based on (e.g.equal to) a leakage factor between a frequency band used by the firstwireless communication device and a frequency band used by the secondwireless communication device.

That the power level threshold is associated with the second power levelmay comprise that the power level threshold equals an interference powervalue that renders performance of a simultaneous reception of a desiredsignal (i.e. the down-link reception) at the second power levelunacceptable. For example, the power level threshold may have a valueequal to the second power level divided by a signal-to-interferenceratio (SIR), or divided by a similar measure (e.g. a signal-to-noiseratio (SNR) or a signal-to-interference-and-noise ratio (SINR).Alternatively, the power level threshold may have a value correspondingto an interference power value where a block error rate (BLER) or biterror rate (BER) of the down-link reception falls above an acceptableerror rate threshold. The second power level may be a second receivedpower level.

The down-link reception may comprise any down-link reception, forexample, reception of down-link data, down-link control signaling,synchronization signals, pilot symbols, reference signals, and/orup-link scheduling grants.

According to some embodiments, detecting the above-identified intentionmay comprise receiving an up-link allocation of the first time-frequencyresource from (a network node of) the first cellular communicationnetwork.

According to some embodiments, detecting the above-identified intentionmay comprise the first wireless communication device autonomouslydetermining to employ the first time-frequency resource for up-linktransmission (and possibly informing the first cellular communicationnetwork of the determination).

Detecting the intention of the first wireless communication device touse a first power level and a first time-frequency resource for up-linktransmission to the first cellular communication network may, accordingto some embodiments, comprise the first wireless communication devicedetecting a need for increased up-link resource allocations,transmitting a corresponding request to a network node of the firstcellular communication network, and receiving an up-link allocation froma network node of the first cellular communication network.

According to some embodiments, the method may further comprise startingthe up-link transmission using the first power level and the firsttime-frequency resource before receiving the interference indication,and stopping the up-link transmission using the first power level andthe first time-frequency resource if it is deter mined, based on theinterference indication, to not use the first time-frequency resourcefor up-link transmission.

In some embodiments, the method may further comprise starting theup-link transmission using the first power level and the firsttime-frequency resource if it is determined, based on the interferenceindication, to use the first time-frequency resource for up-linktransmission.

The method may, according to some embodiments, further comprisemonitoring the third time-frequency resource after detecting theintention.

In some embodiments, the method may further comprise transmitting abeacon signal using a fourth power level associated with the first powerlevel in a fourth time-frequency resource after detecting the intention,and monitoring the third time-frequency resource after transmitting thebeacon signal. In such embodiments, receiving the interferenceindication may be performed in response to transmitting the beaconsignal.

The beacon signal may, for example, comprise data information and/orsynchronization symbols.

That the fourth power level is associated with the first power level maycomprise that the fourth power level is equal to the first power levelmultiplied with a scaling factor (i.e. a fourth power level scalingfactor). The fourth power level scaling factor may be based or (e.g.equal to) a path loss between the first and second wirelesscommunication devices and/or a path loss difference between a carrierfrequency used for the up-link transmission and a carrier frequency usedfor the beacon transmission. Alternatively or additionally, the thirdpower level scaling factor may be based on (e.g. equal to) a leakagefactor between a frequency band used by the first wireless communicationdevice and a frequency band used by the second wireless communicationdevice.

The third and/or fourth power levels may correspond to (e.g. be equalto) a power level of the (expected or actual) interference (caused bythe first wireless communication device) experienced at the secondwireless communication device in the second time-frequency resource.

According to some embodiments, the method may comprise determining tonot use the first time-frequency resource for up-link transmission ifthe interference indication is received. In such embodiments, the methodmay comprise determining to use the first time-frequency resource forup-link transmission if the interference indication is not received.

According to some embodiments, the method may comprise determining touse the first time-frequency resource for up-link transmission if theinterference indication is not received, and if the interferenceindication is received it may be determined whether or not to use thefirst time-frequency resource for up-link transmission based on thecontent of the interference indication. For example, the interferenceindication may have a first value if the third power level of theinterference exceeds the power level threshold and a second value if thethird power level of the interference does not exceed the power levelthreshold. In such embodiments, it may be determined to not use thefirst time-frequency resource for up-link transmission if theinterference indication has the first value and to use the firsttime-frequency resource for up-link transmission if the interferenceindication has the second value.

The method may, in some embodiments, further comprise (if it isdetermined to not use the first time-frequency resource for up-linktransmission) transmitting a report indicative of the determination tothe first cellular communication network.

The first and second cellular communication networks may be the same ordifferent cellular communication networks. In some embodiments, thefirst and second cellular communication networks are networks of a firstoperator and a second operator, respectively, where the first and secondoperators are different operators.

At least one of the first and second cellular communication networks maybe compliant with UMTS LTE according to some embodiments.

The first, second, third and fourth time-frequency resources may be anycombination of any suitable time resource and any suitable frequencyresource. For example, a time resource may comprise a (time) slot, a(time) frame, or a subframe, and a frequency resource may comprise afrequency band, a carrier frequency, and/or a set of carrierfrequencies. In a typical example, a time-frequency resource may be aresource element and/or a set of resource elements of UMTS LTE.

Typically, the first, second, third and fourth time-frequency resourcesare different time-frequency resources (i.e. at least one of the timeand the frequency of the resource differs from the time and thefrequency of the other resources). In some examples, the first andsecond time-frequency resources comprise different times and may or maynot share frequency. In some examples, the third and fourthtime-frequency resources comprise different times and may or may notshare frequency.

In some embodiments, the first and second time-frequency resourcescomprise resources of a cellular communication system (e.g. the systemused in the first and second cellular communication networks) and thethird and fourth time-frequency resources comprise one or more ofresources of a cellular communication system (e UMTS LTE), or otherwireless communication resources such as device-to-device (D2D)communication resources (e.g. Bluetooth, WiFi Direct, network assistedD2D, Wireless Local Area Network—WLAN, etc.).

According to a second aspect, a method is provided for a second wirelesscommunication device adapted to communicate with a second cellularcommunication network.

The method comprises receiving (from a first wireless communicationdevice) a signal indicative of up-link transmission by the firstwireless communication device to a first cellular communication networkusing a first power level and a first time-frequency resource.

The method also comprises deter whether or not an interference (causedby the up-link transmission of the first wireless communication deviceusing the first power level and the first time-frequency resource andaffecting a down-link reception of the second wireless communicationdevice from a second cellular communication network at a second powerlevel in a second time-frequency resource) has a third power levelassociated with the first power level that exceeds a power levelthreshold associated with the second power level. Determining whether ornot the interference has the third power level that exceeds the powerlevel threshold may be based on the received signal.

The method further comprises transmitting an interference indication tothe first wireless communication device using a third time-frequencyresource if it is determined that the third power level of theinterference exceeds the power level threshold.

According to some embodiments, the method may comprise transmitting theinterference indication to the first wireless communication device alsoif it is determined that the third power level of the interference doesnot exceed the power level threshold. In some embodiments, theinterference indication may have a first value if the third power levelof the interference exceeds the power level threshold and a second valueif the third power level of the interference does not exceed the powerlevel threshold.

In some embodiments, the method may comprise not transmitting anyinterference indication to the first wireless communication device if itis determined that the third power level of the interference does notexceed the power level threshold.

In some embodiments, the signal indicative of the up-link transmissionmay comprise a beacon signal received in a fourth time-frequencyresource. In such embodiments, the method may further comprise (first)detecting impaired down-link reception at the second power level in thesecond time-frequency resource by the second wireless communicationdevice and monitoring the fourth time-frequency resource (in response todetecting impaired down-link reception). Then, the beacon signal may bereceived during or in response to the monitoring of the fourthtime-frequency resource.

In some embodiments (e.g. if the first wireless communication device ofthe first aspect commences the up-link transmission causing theinterference may before receiving the interference indication), thesignal indicative of the up-link transmission may comprise the up-linktransmission itself.

According to some embodiments, the method may further comprisetransmitting a report indicative of the determination to the secondcellular communication network if it is determined that the interferencehas the third power level that exceeds the power level threshold.

It should be noted that a wireless communication device may be adaptedto perform one or both of the method according to the first aspect andthe method according to the second aspect.

A third aspect is a computer program product comprising a computerreadable medium, having thereon a computer program comprising programinstructions, the computer program being loadable into a data-processingunit and adapted to cause the data-processing unit to execute methodsteps according to the first and/or second aspect when the computerprogram is run by the data-processing unit.

A fourth aspect is an arrangement for a first wireless communicationdevice adapted to communicate with a first cellular communicationnetwork. The arrangement comprises a detector, a transmitter, a receiverand a determiner.

The detector is adapted to detect an intention of the first wirelesscommunication device to use a first power level and a firsttime-frequency resource for up-link transmission to the first cellularcommunication network.

The transmitter is adapted to perform the up-link transmission using thefirst power level and the first time-frequency resource.

The receiver is adapted to receive an interference indication from asecond wireless communication device in a third time-frequency resource,wherein the interference indication is indicative of whether or not aninterference (caused by the up-link transmission of the first wirelesscommunication device using the first power level and the firsttime-frequency resource and affecting a down-link reception of thesecond wireless communication device from a second cellularcommunication network at a second power level in a second time-frequencyresource) has a third power level associated with the first power levelthat exceeds a power level threshold associated with the second powerlevel.

The determiner is adapted to determine whether or not to use the firsttime-frequency resource for up-link transmission based on theinterference indication.

The receiver may be adapted to receive the interference indication inresponse to the detector detecting the intention. Alternatively oradditionally, the receiver may be adapted to receive the interferenceindication in response to the transmitter performing the up-linktransmission or in response to the transmitter transmitting a beaconsignal.

In some embodiments, the arrangement may further comprise a controller.

The controller may be adapted to cause the transmitter to start theup-link transmission using the first power level and the firsttime-frequency resource responsive to the detector detecting theintention to use the first power level and the first time-frequencyresource for up-link transmission, and to cause the transmitter to stopthe up-link transmission using the first power level and the firsttime-frequency resource responsive to the determiner determining, basedon the interference indication, to not use the first time-frequencyresource for up-link transmission.

Alternatively or additionally, the controller may be adapted to causethe transmitter to start the up-link transmission using the first powerlevel and the first time-frequency resource responsive to the determinerdetermining, based on the interference indication, to use the firsttime-frequency resource for up-link transmission.

The arrangement may, according to some embodiments, further comprise amonitor adapted to monitor the third time-frequency resource responsiveto the detector detecting the intention.

The transmitter may, in some embodiments, be further adapted to transmita beacon signal using a fourth power level associated with the firstpower level in a fourth time-frequency resource responsive to thedetector detecting the intention. In such embodiments, the arrangementmay further comprise a monitor adapted to monitor the thirdtime-frequency resource responsive to the transmitter transmitting thebeacon signal.

According to a fifth aspect, an arrangement is provided for a secondwireless communication device adapted to communicate with a secondcellular communication network. The arrangement comprises a receiver, adeterminer and a transmitter.

The receiver is adapted to receive (from a first wireless communicationdevice) a signal indicative of up-link transmission by the firstwireless communication device to a first cellular communication networkusing a first power level and a first time-frequency resource.

The determiner is adapted to determine whether or not an interference(caused by the up-link transmission of the first wireless communicationdevice using the first power level and the first time-frequency resourceand affecting a down-link reception of the second wireless communicationdevice from a second cellular communication network at a second powerlevel in a second time-frequency resource) has a third power levelassociated with the first power level that exceeds a power levelthreshold associated with the second power level.

The transmitter is adapted to transmit an interference indication to thefirst wireless communication device using a third time-frequencyresource responsive to the determiner determining that the interferencehas the third power level that exceeds the power level threshold.

In some embodiments, the signal indicative of the up-link transmissionmay comprise a beacon signal received in a fourth time-frequencyresource and the arrangement may further comprise a detector and amonitor. The detector may be adapted to detect impaired down-linkreception at the second power level in the second time-frequencyresource by the second wireless communication device. The monitor may beadapted to monitor the fourth time-frequency resource in response to thedetector detecting the impaired down-link reception.

A sixth aspect is an arrangement for a wireless communication devicecomprising the arrangement for the first wireless communication deviceof the fourth aspect and the arrangement for the second wirelesscommunication device of the fifth aspect.

A seventh aspect is a wireless communication device comprising thearrangement of any of the fourth, fifth and sixth aspects.

In some embodiments, the fourth aspect may additionally have featuresidentical with or corresponding to any of the various features asexplained above for the first aspect. Similarly, the fifth aspect mayadditionally have features identical with or corresponding to any of thevarious features as explained above for the second aspect.

An advantage of some embodiments is that flexible time dimensionresource allocation is enabled while managing potential interferencecaused by the flexibility.

Another advantage of some embodiments is that increased networkefficiency may be achieved. The increased network efficiency may be dueto the possibility to flexibly allocate time dimension resources. Theincreased network efficiency may (alternatively or additionally) be dueto the provided interference control mechanism. The increased networkefficiency may (yet alternatively or additionally) be due to that adecision of whether or not to use an allocated resource is based on anactual (or predicted) interference situation in stead of basingallocation decisions on a worst case situation.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects, features and advantages will appear from the followingdetailed description of embodiments, with reference being made to theaccompanying drawings, in which:

FIG. 1 is a schematic drawing of an example scenario according to someembodiments;

FIG. 2 is a combined flowchart and signaling diagram illustratingexample method steps and signals according to some embodiments;

FIG. 3 is a block diagram illustrating an example arrangement accordingto some embodiments;

FIG. 4 is a block diagram illustrating an example arrangement accordingto some embodiments;

FIG. 5 is a block diagram illustrating an example arrangement accordingto some embodiments; and

FIG. 6 is a schematic drawing illustrating a computer readable mediumaccording to some embodiments.

DETAILED DESCRIPTION

The notations “device” and “wireless communication device” will be usedinterchangeably herein.

UMTS LTE may be used as an example in this disclosure. However,embodiments may be equally applicable to other existing or futurecellular communication systems (e.g. Global System for Mobilecommunication (GSM), UMTS, or High Speed Packet Access (HSPA)).

In the following, embodiments will be described where flexible timedimension resource allocation is made possible while managing potentialinterference caused by the flexibility.

Various embodiments may be particularly useful if the flexibleallocation of time dimension resources results in a situation whereuplink transmission is performed by a first wireless communicationdevice in a first cellular communication network and the uplinktransmission may cause interference at a second wireless communicationdevice during downlink reception by the second wireless communicationdevice in a second cellular communication network. In such situations,some embodiments may eliminate or at least mitigate interference causedby the uplink transmission in the first cellular communication networkand affecting the downlink reception in the second cellularcommunication network.

In some embodiments, it is detected whether there are any (second)devices in the vicinity of a first device, wherein the first deviceneeds to transmit using a time-frequency resource for cellularcommunication where there is a risk of causing significant interferenceto the other (second) devices cellular communication reception. Thevicinity (or proximity) detection may be based on measurements orestimations of the propagation attenuation (path loss) between the firstand second devices. The detection may utilize D2D communication.

According to some embodiments, an intention of a first wirelesscommunication device to use a first power level and a firsttime-frequency resource for up-link transmission to a first cellularcommunication network is detected and a signal indicative of up-linktransmission (e.g. the uplink transmission itself or a beacon signal)from the first device is received at a second wireless communicationdevice. The second device determines whether or not an interference(caused by the up-link transmission of the first device and affecting adown-link reception of the second device from a second cellularcommunication network at a second power level in a second time-frequencyresource) has a third power level associated with the first power levelthat exceeds a power level threshold associated with the second powerlevel, and transmits an interference indication to the first deviceusing a third time-frequency resource if it is determined that the thirdpower level exceeds the power level threshold. Thereafter, the firstdevice determines whether or not to use the first time-frequencyresource for up-link transmission based on the interference indication.

Thus, an extra uplink resource allocated to a device is typically onlyused if the corresponding uplink transmission does not causeinterference to downlink reception of nearby devices, which reduces theinterference in the systems. Furthermore, the flexible resourceallocation does not have to be designed for worst case scenarios, and,thus, extra uplink resources may be allocated more often than in a worstcase scenario based approach, which increases system efficiency.

FIG. 2 is a combined flowchart and signaling diagram illustratingexample method steps and signals according to some embodiments. Eachmethod step is executed by either of a first wireless communicationdevice (UE1) 201 (compare with the first wireless communication device101 of FIG. 1) and a second wireless communication device (UE2) 202(compare with the second wireless communication device 102 of FIG. 1).Each signaling event takes place between the first device 201 and thesecond device 202, between the first device 201 and a network node (NW1)203 of a first cellular communication network (compare with network node111 of FIG. 1), or between the second device 202 and a network node(NW2) 204 of a second cellular communication network (compare withnetwork node 112 of FIG. 1).

In step 211, UE1 detects an intention to use an extra uplink resource(i.e. a first power level and a first time-frequency resource forup-link transmission to the first cellular communication network).

Detecting the above-identified intention in step 211 may comprisereceiving an up-link allocation 234 from NW1 as illustrated by sub-step214.

Alternatively, detecting the above-identified intention in step 211 maycomprise UE1 autonomously determining to employ the extra uplinkresource (and possibly informing NW1 of the determination).

Alternatively or additionally, detecting the above-identified intentionin step 211 may comprise detecting a need for increased up-link resourceallocations (sub-step 212), transmitting a corresponding request 233 toNW1 (sub-step 213), and receiving an up-link allocation 234 from NW1(sub-step 214).

Then, UE1 performs one or both of starting the up-link transmission 235(also reaching UE2 as interference 245) using the extra uplink resourceaccording to step 215 and transmitting a beacon signal 246 according tostep 216. The beacon may be transmitted using a fourth power level in afourth time-frequency resource (e.g. a D2D time-frequency resource). Thefourth power level of the beacon may be associated with the first powerlevel of the up-link transmission. For example, the power level of thebeacon may be selected such that the power level of the beacon, when itis received at UE2, corresponds to the power level of the up-linktransmission induced interference when it is received at UE2 (i.e. thethird power level). The beacon may be indicative of the firsttime-frequency resource and/or of the first power level.

According to one example the power level of the beacon may be selectedaccording to the following approach, e.g. if D2D communication is usedfor transmission of the beacon (and possibly for transmission of theinterference indication). A suitable path loss model (e.g. that thepower at a distance r from a transmitter equals P_(tx)/r³ where P_(tx)is the output power of the transmitter) is assumed. It is also assumedthat the transmit power for the cellular up-link transmission is known,and that the approximate received power level when interference causedby the up-link transmission is harmful to cellular down-link reception(in a same or different frequency interval as the up-link transmission)is known. Then, a radius may be determined of the dead zone area(compare with 131 of FIG. 1) in which down-link reception will beharmfully interfered by the interference caused by the up-linktransmission. Given a known reference sensitivity level for the D2Dcommunication, the first device may then calculate the transmissionpower level of the beacon such that a second device is in the dead zonearea if it detects the beacon. In response to step 215 and/or inresponse to step 216, UE1 may monitor a resource for transmission of aninterference indication 248, 249 as illustrated in step 217. Theresource for transmission of the interference indication may be a thirdtime-frequency resource (e.g. a D2D time-frequency resource).

It should be noted that a selection of the steps 215, 216 and 217 may beexecuted in any suitable order (e.g. 215, 216, 217; or 216, 217, 215; or216, 215, 217; or 215, 217; or 216, 217). Furthermore, step 215 may beexecuted in parallel to one or more of steps 216 and 217. Othersequences of execution are also possible.

As illustrated by step 251, UE2 may be carrying out reception ofdownlink signaling 261 from NW2 at a second received power level in asecond time-frequency resource and, in step 252, UE2 receives a signal245, 246 indicative of the up-link transmission 235 by The signalindicative of the up-link transmission may be a beacon signal 246 (asillustrated by sub-step 255) and/or an interference 245 caused by theup-link transmission 235.

According to some embodiments, step 252 may comprise UE2 detectingimpaired down-link reception (sub-step 253) and monitoring the fourthtime-frequency resource (sub-step 254) in response thereto beforereceiving a beacon signal 246 (sub-step 255).

The down-link reception may be any applicable down-link reception (e.g.down-link data reception, reception of synchronization signals, and/ordetection of downlink control signals). Thus, step 253 may, for example,comprise detecting synchronization problems.

Based on the signal(s) received in step 252, UE2 determines (in step256) whether or not the received power level of the interference (causedby the up-link transmission of UE1 and affecting the down-link receptionof UE2) exceeds a power level threshold. The power level threshold maybe set in association with the power level of the received down-linksignal, for example, such that the power level threshold equals aninterference power value that renders down-link reception performanceunacceptable.

Step 256 may, for example, comprise comparing a power level of thereceived interference 245 to the power level threshold. Alternatively oradditionally, step 256 may comprise comparing a power level of thereceived beacon signal 246 to the power level threshold.

If it is determined that the power level of the interference exceeds thepower level threshold (No-path out from step 256), UE2 transmits aninterference indication 248 to UE1 as illustrated by step 257. Theinterference indication may take the form of a response signal as areaction to a received beacon signal or may take the form of analternative beacon signal if no beacon was transmitted by the firstdevice. Possibly, UE2 also transmits a report 269 indicative of thedetermination to NW2 as illustrated by step 259.

If it is determined that the power level of the interference does notexceed the power level threshold (Yes-path out from step 256), UE2 maytransmit an interference indication 249 to UE1 as illustrated by step258, wherein the interference indication 249 has another content thanthe interference indication 248 and is indicative of the power level ofthe interference not exceeding the power level threshold. Alternatively,UE2 may not transmit any interference indication at all to UE1 if it isdetermined that the power level of the interference does not exceed thepower level threshold (Yes-path out from step 256).

The resource for transmission of the interference indication 248, 249may be the third time-frequency resource (e.g. a D2D time-frequencyresource).

In step 218, UE1 receives the interference indication 248, 249transmitted by UE2 and in step 219 UE1 determines whether or not to usethe extra up-link resource based on the interference indication.

If it is determined to use the extra up-link resource (Yes-step out fromstep 219), UE1 may start up-link transmission 238 accordingly asillustrated in step 220 (or continue up-link transmission if up-linktransmission has already been started in step 215).

If it is determined to not use the extra up-link resource (No-step outfrom step 219), UE1 may prohibit up-link transmission in the extraup-link resource (or stop up-link transmission if up-link transmissionhas already been started in step 215, as illustrated in step 221).

In step 223, UE1 may transmit a report 239 to NW1 indicative of thedetermination if it is determined to not use the extra up-link resource.The information of this report may be used by NW1 to improve theefficiency of further allocations to UE1.

The determination of step 219 may, for example, comprise determining tonot use the extra up-link resource if the interference indication 248 isreceived. In some embodiments, it may be determined to use the extraup-link resource if the interference indication 249 is received. If noresponse (i.e. neither of 248 or 249) is received, it may be determinedto use the extra up-link resource according to some embodiments.

In some embodiments, it may be deter mined to use the extra up-linkresource even if the interference indication 248 is received. In suchembodiments, UE1 may, for example, determine to use a lower power levelthan the first power level for the up-link transmission.

Of course, there could be a plurality of first devices and/or aplurality of second devices, wherein each pair may operate in accordancewith the methods of FIG. 2.

Three example scenarios where embodiments are applicable will now bedescribed. Various features of the embodiments of these scenarios may betaken alone and combined with features of any other suitable embodiment.For example, the example selection of frequencies and/or power levelsmay be applied similarly in other embodiments.

In a first example scenario, a first device determines a need forup-link transmission at a first power level on a first time-frequencyresource (which may specify e.g. a carrier frequency F1 and a timeinstant T1 and/or another type of time-frequency resource). The firstdevice starts to transmit a beacon signal. The beacon signaltransmission may preferably, but not necessarily, be done using anothercarrier frequency F2 (and possibly another Radio Access Technology—RAT).The power level of the beacon transmission may be based on the range ofa “dead zone” (see 131 of FIG. 1) around the first device. Thus, thepower level of the beacon transmission may be a proportional to thetransmit power (e.g. spectral density) used for up-link transmission onF1.

A second device in the vicinity of the first device monitors the carrierfrequency where the beacon is transmitted. If the second device detectsthe beacon signal, it transmits a response signal. The first devicereceives the response signal, which indicates that there is a seconddevice in vicinity of the first device that might be affected byinterference caused by the up-link transmission at first time-frequencyresource (F1, T1). The first device determines accordingly to nottransmit at time T1 and reports the decision to the network node it isconnected to. However, if the second device does not detect the beaconsignal, or if the beacon signal is received at the second device withsufficiently low power, it may be concluded that the first device maytransmit without disturbing the second device.

In a second example scenario, a first device is connected to a network(NW) node. The up-link transmission takes place on carrier frequency F1using a first RAT (LTE for instance) and the first device detects a needfor extended UL slot allocation (e.g. using a first set oftime-frequency resources). The determination may comprise determiningthat an UL buffer of the first device is full and the first device mayrequest an extended UL slot allocation from the NW node accordingly.Alternatively or additionally, the determination may comprise receivinga request from the NW node. The required TX power (or spectral density,i.e. in dBm/Hz) for the UL transmission is determined either by thefirst device, by the NW node, or by cooperation between the first deviceand the NW node.

Then, the first device starts to transmit a beacon signal. The beaconmay be transmitted on the same frequency as the up-link transmission oron another carrier F2 (using the same RAT as the cellular communicatingor possibly a second RAT, e.g. Win Direct). The choice of RAT may dependon the carrier F2 used for the beacon (e.g. Bluetooth or WiFi Direct forF2 in the ISM band and UMTS LTE for F2 in the cellular spectrum). Thebeacon signal may comprise information regarding carrier frequency F1,first time-frequency resources and intended TX power of the up-linktransmission. The beacon signal may be transmitted with a TX powerproportional to the TX power used for transmitting the up-link signal onF1. The proportionality factor may be chosen such that the coverage ofthe beacon signal is matched with the “dead zone” area of the up-linktransmission. Hence, if a second device detects the beacon signal, thesecond device is within a range from the first device where there is arisk of significant interference caused by the first device (e.g. due toTX leakage) for signal reception at a frequency F3 (which may or may notbe the same as F1). The proportionality factor may also or alternativelybe based on leakage requirements from the (3GPP) specifications and/orthe particular carrier frequencies F1 and F2. Selection ofproportionality factor may also include suitable channel models atcarrier frequencies F1 and F2 in order to determine a suitable TX powerfor correct coverage of the beacon. In some embodiments, the TX power ofthe beacon is constant and the beacon signal indicates a received signalstrength threshold (e.g. a value relative to the total signal strengthof a beacon signal or a value relative to the signal strength of areference signal such as a pilot or synchronization signal). If thesecond device detects the beacon at signal strength above the signalstrength threshold, it may conclude that it will be interfered by anup-link transmission of the first device. If the second device detectsthat there is a risk of interference caused by the first device, ittransmits a response signal.

The first device starts to monitor for response signals (e.g. on acarrier at time instances associated with the transmission of the beaconsignal) as soon as the beacon transmission starts. In a particularexample, the first device also starts to use first time-frequencyresource for UL transmission directly after the need is detected. Inthat case, the monitoring of response signals as well as thetransmission of beacon signals may continue during the entire extendedUL transmission session. In some examples, the beacon signal may be sentwith certain intervals and the response signal monitoring may be adaptedcorrespondingly

If no response signal is detected the first device starts (or continues)the up-link transmission using the first time-frequency resource. If aresponse signal is detected the first device may stop any on-goingup-link transmission (or refrain from starting up-link transmissionusing the first time-frequency resource). The first device may informthe NW node about the response signal detection (e.g. using atime-frequency resource different form the first time-frequencyresource).

In a third example scenario, a second device is communicating with a NWnode on a carrier F3. It regularly (e.g. on request or reconfigurationfrom the NW node) monitors a second carrier F2 for beacon signals. Insome examples, the monitoring may be started autonomously if the seconddevice detects an interference or synchronization problem in certain DLslots.

If a beacon signal is detected fulfilling certain characteristics, thesecond device transmits a response signal on a carrier associated to thebeacon transmit carrier F2. The certain characteristics may comprisethat information included in the beacon signal indicates an interferencerisk for reception by the second device at a certain time-frequencyresource (e.g. F3, T1). Hence, if the received beacon indicatesinterference risk on a carrier where the second device is not receivingdown-link signaling, no response signal should be transmitted.Furthermore, if the beacon signal is detected hut the signal level ofthe down-link reception from the NW node is high enough (e.g. above athreshold), no response signal should be transmitted.

In some embodiments, the second device may also report the detectedbeacon signal to the NW node (e.g. using a set of time-frequencyresources different from the ones used for the response signal). Forexample, if the first device estimates its transmission duration andincludes that information in the beacon signal, then the second devicemay inform its NW node accordingly and request that the interferedtime-frequency resource for down-link transmission is not used duringthat duration.

In some embodiments, the second device may include its estimated DLreception duration in the response signal, and the first device may usethat information to inform its own NW node accordingly and request thatthe interfering time-frequency resources for up-link transmission is notused during that duration.

FIGS. 3-5 illustrate example arrangements according to some embodiments.FIG. 3 illustrate an arrangement for a first device (compare with thewireless communication device 101 of FIG. 1 and UE1 of FIG. 2), FIG. 4illustrate an arrangement for a second device (compare with the wirelesscommunication device 102 of FIG. 1 and UE2 of FIG. 2), and FIG. 5illustrate an arrangement for a device that implement a combination ofthe functionality of the first and second devices described above.

The arrangement 300 of FIG. 3 may, for example, be adapted to performthe method steps of UE1 as illustrated in FIG. 2 and it comprises adetector (DETEC1) 330, a combined transmitter and receiver (RX/TX) 310,a determiner (DETER1) 340 and—optionally—a controller (CNTR) 350 and amonitor (MON1) 320.

The detector 330 is adapted to detect an intention to use an extraup-link resource (a first time-frequency resource for up-linktransmission to the first cellular communication network) fortransmission at a first power level (compare with step 211 of FIG. 2),and the transmitter 310 is adapted to perform the up-link transmission(compare with steps 215 and 220 of FIG. 2). The transmitter 310 may alsobe adapted to transmit a beacon signal using a fourth power level in afourth time-frequency resource (compare with step 216 of FIG. 2).

The receiver 310 is adapted to receive an interference indication from asecond wireless communication device in a third time-frequency resource,wherein the interference indication is indicative of whether or not aninterference, caused by the up-link transmission of the first wirelesscommunication device using the first power level and the firsttime-frequency resource and affecting a down-link reception of thesecond wireless communication device from a second cellularcommunication network at a second power level in a second time-frequencyresource, has a third power level associated with the first power levelthat exceeds a power level threshold associated with the second powerlevel (compare with step 218 of FIG. 2). To this end the monitor 320 maybe adapted to monitor the third time-frequency resource (compare withstep 217 of FIG. 2). The monitor 320 and the receiver 310 may be adaptedto perform these activities in response to the transmitter transmittingthe beacon and/or performing the up-link transmission.

The determiner 340 is adapted to determine whether or not to use thefirst time-frequency resource for up-link transmission based on theinterference indication (compare with step 219 of FIG. 2).

The transmitter 310 may be further adapted to transmit a report to anetwork node if it is determined to not use the first time-frequencyresource for up-link transmission (compare with step 223 of FIG. 2).

The controller 350 may be adapted to cause the transmitter 310 to startthe up-link transmission responsive to the detector 330 detecting theintention to use the extra up-link resource (compare with step 215 ofFIG. 2), and to cause the transmitter 310 to stop the up-linktransmission (compare with step 221 of FIG. 2) responsive to thedeterminer 340 determining to not use the first time-frequency resourcefor up-link transmission.

Alternatively or additionally, the controller 350 may be adapted tocause the transmitter 310 to start the up-link transmission responsiveto the determiner 340 determining to use the first time-frequencyresource for up-link transmission (compare with step 220 of FIG. 2).

The arrangement 400 of FIG. 4 may, for example, be adapted to performthe method steps of UE2 as illustrated in FIG. 2 and it comprises adetector (DETEC2) 430, a combined transmitter and receiver (RX/TX) 410,a determiner (DETER2) 440 and—optionally—a monitor (MON2) 420.

The receiver 410 is adapted to receive down-link transmissions from asecond cellular communication network (compare with step 251 of FIG. 2)and to receive, from a first wireless communication device, a signalindicative of up-link transmission by the first wireless communicationdevice using a first power level and a first time-frequency resource(compare with step 252 of FIG. 2).

The determiner 440 is adapted to determine (based on the received signalindicative of up-link transmission) whether or not an interference,caused by the up-link transmission of the first wireless communicationdevice using the first power level and the first time-frequency resourceand affecting a down-link reception of the second wireless communicationdevice from a second cellular communication network at a second powerlevel in a second time-frequency resource, has a third power levelassociated with the first power level that exceeds a power levelthreshold associated with the second power level (compare with step 256of FIG. 2).

The transmitter 410 is adapted to transmit an interference indication tothe first wireless communication device using a third time-frequencyresource responsive to the determiner determining that the interferencehas the third power level that exceeds the power level threshold(compare with steps 257 and 258 of FIG. 2). The transmitter may also beadapted to transmit a report indicative of the determination by thedeterminer 440 to a cellular communication network (compare with step259 of FIG. 2).

The detector 430 may be adapted to detect impaired down-link reception(compare with step 253 of FIG. 2), and the monitor 420 may be adapted tomonitor a fourth time-frequency resource (for a beacon signal indicativeof the up-link transmission) in response to the detector 430 detectingthe impaired down-link reception (compare with step 254 of FIG. 2).

The arrangement 500 of FIG. 5 is a combination of the arrangement 300 ofFIG. 3 and the arrangement 400 of FIG. 4. The arrangement 500 comprisesa detector (DETEC1) 532 corresponding to the detector 330, a determiner(DETER1) 541 corresponding to the determiner 340, a controller (CNTR)550 corresponding to the controller 350, a monitor (MON1) 521corresponding to the monitor 320, a detector (DETEC2) 532 correspondingto the detector 430, a determiner (DETER2) 542 corresponding to thedeterminer 440, a monitor (MON2) 522 corresponding to the monitor 420,and a combined transmitter and receiver (RX/TX) 510 corresponding to thecombined transmitter and receiver 3110 and to the combined transmitterand receiver 410.

The described embodiments and their equivalents may be realized insoftware or hardware or a combination thereof. They may be performed bygeneral-purpose circuits associated with or integral to a communicationdevice, such as digital signal processors (DSP), central processingunits (CPU), co-processor units, field-programmable gate arrays (FPGA)or other programmable hardware, or by specialized circuits such as forexample application-specific integrated circuits (ASIC). All such formsare contemplated to be within the scope of this disclosure.

Embodiments may appear within an electronic apparatus (such as awireless communication device) comprising circuitry/logic or performingmethods according to any of the embodiments. The electronic apparatusmay, for example, be a portable or handheld mobile radio communicationequipment, a mobile radio terminal, a mobile telephone, a communicator,an electronic organizer, a smartphone, a computer, a notebook, aUSB-stick, a plug-in card, an embedded drive, a user equipment (UE), amodem, a sensor, or a mobile gaming device.

According to some embodiments, a computer program product comprises acomputer readable medium such as, for example, a diskette or a CD-ROM(such as the CD-ROM 600 illustrated in FIG. 6). The computer readablemedium may have stored thereon a computer program comprising programinstructions. The computer program may be loadable into adata-processing unit, which may, for example, be comprised in a mobileterminal. When loaded into the data-processing unit, the computerprogram may be stored in a memory associated with or integral to thedata-processing unit. According to some embodiments, the computerprogram may, when loaded into and run by the data-processing unit, causethe data-processing unit to execute method steps according to, forexample, the method shown in FIG. 3.

In the following a number of illustrative embodiments are disclosed asexamples 1 to 23.

1. A method for a first wireless communication device adapted tocommunicate with a first cellular communication network, the methodcomprising: detecting an intention of the first wireless communicationdevice to use a first power level and a first time-frequency resourcefor up-link transmission to the first cellular communication network;receiving an interference indication from a second wirelesscommunication device in a third time-frequency resource, wherein theinterference indication is indicative of whether or not an interference,caused by the up-link transmission of the first wireless communicationdevice using the first power level and the first time-frequency resourceand affecting a down-link reception of the second wireless communicationdevice from a second cellular communication network at a second powerlevel in a second time-frequency resource, has a third power levelassociated with the first power level that exceeds a power levelthreshold associated with the second power level; and determiningwhether or not to use the first time-frequency resource for up-linktransmission based on the interference indication.

2. The method of example 1 further comprising starting the up-linktransmission using the first power level and the first time-frequencyresource before receiving the interference indication, and stopping theup-link transmission using the first power level and the firsttime-frequency resource if it is determined, based on the interferenceindication, to not use the first time-frequency resource for up-linktransmission.

3. The method of example 1 further comprising starting the up-linktransmission using the first power level and the first time-frequencyresource if it is determined, based on the interference indication, touse the first time-frequency resource for up-link transmission.

4. The method of any of examples 1 through 3 further comprisingmonitoring the third time-frequency resource after detecting theintention.

5. The method of any of examples 1 through 3 further comprisingtransmitting a beacon signal using a fourth power level associated withthe first power level in a fourth time-frequency resource afterdetecting the intention, and monitoring the third time-frequencyresource after transmitting the beacon signal, and wherein receiving theinterference indication is performed in response to transmitting thebeacon signal.

6. The method of any of examples 1 through 5 wherein detecting theintention comprises receiving an up-link allocation of the firsttime-frequency resource from the first cellular communication network.

7. The method of any of examples 1 through 6 comprising determining tonot use the first time-frequency resource for up-link transmission ifthe interference indication is received.

8. The method of any of examples 1 through 7 further comprising, if itis determined to not use the first time-frequency resource for up-linktransmission, transmitting a report indicative of the determination tothe first cellular communication network.

9. A method for a second wireless communication device adapted tocommunicate with a second cellular communication network, the methodcomprising: receiving, from a first wireless communication device, asignal indicative of up-link transmission by the first wirelesscommunication device to a first cellular communication network using afirst power level and a first time-frequency resource; determiningwhether or not an interference, caused by the up-link transmission ofthe first wireless communication device using the first power level andthe first time-frequency resource and affecting a down-link reception ofthe second wireless communication device from a second cellularcommunication network at a second power level in a second time-frequencyresource, has a third power level associated with the first power levelthat exceeds a power level threshold associated with the second powerlevel; and transmitting an interference indication to the first wirelesscommunication device using a third time-frequency resource if it isdetermined that the interference has the third power level that exceedsthe power level threshold.

10. The method of example 9 wherein the signal indicative of the up-linktransmission comprises a beacon signal received in a fourthtime-frequency resource and further comprising: detecting impaireddown-link reception at the second power level in the secondtime-frequency resource by the second wireless communication device; andmonitoring the fourth time-frequency resource.

11. The method of any of examples 9 through 10 further comprisingtransmitting a report indicative of the determination to the secondcellular communication network if it is determined that the interferencehas the third power level that exceeds the power level threshold.

12. A computer program product comprising a computer readable medium,having thereon a computer program comprising program instructions, thecomputer program being loadable into a data-processing unit and adaptedto cause execution of the method according to any of examples 1 through11 when the computer program is run by the data-processing unit.

15. An arrangement for a first wireless communication device adapted tocommunicate with a first cellular communication network, the arrangementcomprising: a detector adapted to detect an intention of the firstwireless communication device to use a first power level and a firsttime-frequency resource for up-link transmission to the first cellularcommunication network; a transmitter adapted to perform the up-linktransmission using the first power level and the first time-frequencyresource; a receiver adapted to receive an interference indication froma second wireless communication device in a third time-frequencyresource, wherein the interference indication is indicative of whetheror not an interference, caused by the up-link transmission of the firstwireless communication device using the first power level and the firsttime-frequency resource and affecting a down-link reception of thesecond wireless communication device from a second cellularcommunication network at a second power level in a second time-frequencyresource, has a third power level associated with the first power levelthat exceeds a power level threshold associated with the second powerlevel; and a determiner adapted to determine whether or not to use thefirst time-frequency resource for up-link transmission based on theinterference indication.

16. The arrangement of example 15 further comprising a controlleradapted to cause the transmitter to start the up-link transmission usingthe first power level and the first time-frequency resource responsiveto the detector detecting the intention to use the first power level andthe first time-frequency resource for up-link transmission, and to causethe transmitter to stop the up-link transmission using the first powerlevel and the first time-frequency resource responsive to the determinerdetermining, based on the interference indication, to not use the firsttime-frequency resource for up-link transmission.

17. The arrangement of example 15 further comprising a controlleradapted to cause the transmitter to start the up-link transmission usingthe first power level and the first time-frequency resource responsiveto the determiner determining, based on the interference indication, touse the first time-frequency resource for up-link transmission.

18. The arrangement of any of examples 15 through 17 further comprisinga monitor adapted to monitor the third time-frequency resourceresponsive to the detector detecting the intention.

19. The arrangement of any of examples 15 through 17 wherein thetransmitter is further adapted to transmit a beacon signal using afourth power level associated with the first power level in a fourthtime-frequency resource responsive to the detector detecting theintention, and further comprising a monitor adapted to monitor the thirdtime-frequency resource responsive to the transmitter transmitting thebeacon signal.

20. An arrangement for a second wireless communication device adapted tocommunicate with a second cellular communication network, thearrangement comprising: a receiver adapted to receive, from a firstwireless communication device, a signal indicative of up-linktransmission by the first wireless communication device to a firstcellular communication network using a first power level and a firsttime-frequency resource; a determiner adapted to determine whether ornot an interference, caused by the up-link transmission of the firstwireless communication device using the first power level and the firsttime-frequency resource and affecting a down-link reception of thesecond wireless communication device from a second cellularcommunication network at a second power level in a second time-frequencyresource, has a third power level associated with the first power levelthat exceeds a power level threshold associated with the second powerlevel; and a transmitter adapted to transmit an interference indicationto the first wireless communication device using a third time-frequencyresource responsive to the determiner determining that the interferencehas the third power level that exceeds the power level threshold.

21. The arrangement of example 20 wherein the signal indicative of theup-link transmission comprises a beacon signal received in a fourthtime-frequency resource and further comprising: a detector adapted todetect impaired down-link reception at the second power level in thesecond time-frequency resource by the second wireless communicationdevice; and a monitor adapted to monitor the fourth time-frequencyresource in response to the detector detecting the impaired down-linkreception.

22. An arrangement for a wireless communication device comprising thearrangement for the first wireless communication device of any ofexamples 15 through 19 and the arrangement for the second wirelesscommunication device of any of examples 20 through 21.

23. A wireless communication device comprising the arrangement of any ofthe examples 15 through 22.

Reference has been made herein to various embodiments. However, a personskilled in the art would recognize numerous variations to the describedembodiments that would still fall within the scope of the claims. Forexample, the method embodiments described herein describes examplemethods through method steps being performed in a certain order.However, it is recognized that these sequences of events may take placein another order without departing from the scope of the claims.Furthermore, some method steps may be performed in parallel even thoughthey have been described as being performed in sequence.

In the same manner, it should be noted that in the description ofembodiments, the partition of functional blocks into particular units isby no means limiting. Contrarily, these partitions are merely examples.Functional blocks described herein as one unit may be split into two ormore units. In the same manner, functional blocks that are describedherein as being implemented as two or more units may be implemented as asingle unit without departing from the scope of the claims.

Hence, it should be understood that the details of the describedembodiments are merely for illustrative purpose and by no meanslimiting. Instead, all variations that fall within the range of theclaims are intended to be embraced therein.

The invention claimed is:
 1. A method for a second wirelesscommunication device configured to communicate with a second cellularcommunication network, the method comprising: receiving, from a firstwireless communication device, a signal indicative of up-linktransmission by the first wireless communication device to a firstcellular communication network using a first power level and a firsttime-frequency resource; determining whether or not an interference,caused by the up-link transmission of the first wireless communicationdevice using the first power level and the first time-frequency resourceand affecting a down-link reception of the second wireless communicationdevice from a second cellular communication network at a second powerlevel in a second time-frequency resource, has a third power levelassociated with the first power level that exceeds a power levelthreshold associated with the second power level; and transmitting aninterference indication to the first wireless communication device usinga third time-frequency resource if it is determined that theinterference has the third power level that exceeds the power levelthreshold.
 2. The method of claim 1 wherein the signal indicative of theup-link transmission comprises a beacon signal received in a fourthtime-frequency resource and further comprising: detecting impaireddown-link reception at the second power level in the secondtime-frequency resource by the second wireless communication device; andmonitoring the fourth time-frequency resource.
 3. The method of claim 1further comprising transmitting a report indicative of the determinationto the second cellular communication network if it is determined thatthe interference has the third power level that exceeds the power levelthreshold.
 4. An arrangement for a second wireless communication devicethat is configured to communicate with a second cellular communicationnetwork, the arrangement comprising: a receiver configured to receive,from a first wireless communication device, a signal indicative ofup-link transmission by the first wireless communication device to afirst cellular communication network using a first power level and afirst time-frequency resource; a determiner configured to determinewhether or not an interference, caused by the up-link transmission ofthe first wireless communication device using the first power level andthe first time-frequency resource and affecting a down-link reception ofthe second wireless communication device from a second cellularcommunication network at a second power level in a second time-frequencyresource, has a third power level associated with the first power levelthat exceeds a power level threshold associated with the second powerlevel; and a transmitter configured to transmit an interferenceindication to the first wireless communication device using a thirdtime-frequency resource responsive to the determiner determining thatthe interference has the third power level that exceeds the power levelthreshold.
 5. The arrangement of claim 4 wherein the signal indicativeof the up-link transmission comprises a beacon signal received in afourth time-frequency resource and further comprising: a detectorconfigured to detect impaired down-link reception at the second powerlevel in the second time-frequency resource by the second wirelesscommunication device; and a monitor configured to monitor the fourthtime-frequency resource in response to the detector detecting theimpaired down-link reception.
 6. An arrangement for a wirelesscommunication device comprising: an arrangement for a first wirelesscommunication device; and an arrangement for the second wirelesscommunication device of claim 4, wherein the first wirelesscommunication device is configured to communicate with a first cellularcommunication network, the arrangement for the first wirelesscommunication device comprising: a detector configured to detect anintention of the first wireless communication device to use a firstpower level and a first time-frequency resource for up-link transmissionto the first cellular communication network; a transmitter configured toperform the up-link transmission using the first power level and thefirst time-frequency resource; a receiver configured to receive aninterference indication from a second wireless communication device in athird time-frequency resource, wherein the interference indication isindicative of whether or not an interference, caused by the up-linktransmission of the first wireless communication device using the firstpower level and the first time-frequency resource and affecting adown-link reception of the second wireless communication device from asecond cellular communication network at a second power level in asecond time-frequency resource, has a third power level associated withthe first power level that exceeds a power level threshold associatedwith the second power level; and a determiner configured to determinewhether or not to use the first time-frequency resource for up-linktransmission based on the interference indication.
 7. A wirelesscommunication device comprising the arrangement of claim 4.